LONDON, England --The British government has been accused of basing its latest Iraq dossier on old material, including an article by an American post-graduate student.

Large chunks of the 19-page report -- highlighted by U.S. Secretary of State Colin Powell at the U.N. as a "fine paper ... which describes in exquisite detail Iraqi deception activities" -- contains large chunks lifted from other sources, according to several academics.

British Prime Minister Tony Blair's office, which posted the dossier on its Web site, said the report was "accurate" and that the government never claimed exclusive authorship.

Academics told Britain's Channel 4 news on Thursday that the "bulk" of the report was lifted from three sources, an article in the Middle East Review of International Affairs by Ibrahim al-Marashi, a research associate at the Center for Nonproliferation Studies in Monterey, California.

Glen Rangwala, a lecturer in politics at Cambridge University, told Channel 4 that large chunks of al-Marashi's paper had been copied to form parts of the UK dossier, entitled "Iraq: Its Infrastructure of Concealment, Deception and Intimidation."

"The British government's dossier is 19 pages long and most of pages 6 to 16 are copied directly from that document word for word, even the grammatical errors and typographical mistakes," Rangwala said.

"Many of the words and phrases I recalled from another context, so I searched around the articles I had read about Iraq's military and security organisations and realised that large sections of the government's dossier were actually copied.

Al-Marashi's article, published last September, was based on information obtained at the time of the 1991 Gulf War, Rangwala said.

"The information he was using is 12 years old and he acknowledges this in his article. The British government, when it transplants that information into its own dossier, does not make that acknowledgement.

"So it is presented as current information about Iraq, when really the information it is using is 12 years old."

A spokeswoman for No. 10 Downing Street told CNN: "This was a government briefing paper which was compiled from a number of sources including intelligence material.

"The first and third sections of the report went to the issues of Iraq's non-compliance with United Nations resolutions. This information was largely intelligence based.

"Section Two dealt with historical background on Iraq, and some of it was based on material written by Dr Ibrahim al-Marashi. In retrospect we should have acknowledged any references to material we used that had been written by Dr Ibrahim. We have learnt an important lesson.

"But this issue does not take away to any degree from the accuracy of the information in the report nor does it negate to any extent the core argument put forward that Iraq is involved in deliberate acts of deception," she said.

International affairs expert Dan Plesch of the Royal United Services Institute in London told Channel 4 that the alleged plagiarism was "scandalous."

"This document is clearly presented to the British public as the product of British intelligence and it clearly is nothing of the kind."

He said it was "dressed up as the best MI6 and our other international partners can produce on Saddam."

"The word 'scandalous' is, I think, greatly overused in our political life but it certainly applies to this."

Shadow defence secretary Bernard Jenkin of the opposition Conservative party said: "The government's reaction to the Channel 4 news report utterly fails to explain, deny or excuse the allegations made in the programme.

"This document has been cited by the prime minister and Colin Powell as the basis for a possible war. Who is responsible for such an incredible failure of judgment?

"The Channel 4 report clearly suggests that the intelligence has been embroidered from other sources. Who is the author and who gave their approval?

"We need a clear assurance that the government's published information is based on the best available sources and is not just spin."

The document claims that Iraqi agents have been hiding vital material from UN weapons inspectors under houses and mosques.

It also argues that UN inspectors are outnumbered 200 to one by Iraqi agents trying to obstruct them.